324 
Selected Articles. 
to contain bi-chloride of platina in solution, and the second to 
be mixed with the chloride of the same metal. If the ethiops 
be moistened with formic acid before treating it with hydro- 
chloric acid, neither of the chlorides are formed. It there- 
fore, is evident, that it is the condensed oxygen that decom- 
poses the hydrochloric acid, and disengages the chlorine, 
which the moment it is extricated, combines with the platina. 
The chloride becomes so mixed with the platina that this 
latter ceases to absorb oxygen. If it be treated with potash, 
the chloride is decomposed, and the absorbing and condensing 
properties of the metal are restored to it. 
Oxalic acid dissolved in water, is also transformed into 
carbonic acid by the ethiops of platina, but with less rapidity 
than formic acid ; and even oxalates and formiates dissolved 
in water deprive it of its oxygen, and are transformed into 
carbonates. This reaction is certainly very remarkable, and 
serves to prove that the oxygen in the ethiops is not che- 
mically combined with it, but only condensed in a me- 
chanical manner ; for none of the oxides of platina act like 
oxydizing bodies on these salts. This fact, and the circum- 
stance that platina disoxygenized by formic acid, hydrogen 
or alcohol, rapidly absorbs oxygen from the air, and con- 
denses it to such a degree that it can chemically combine 
with certain organic substances, explain the continued oxydi- 
zing faculty of platina, in the apparatus for the formation of 
acetic acid, described by me, as well as the development of 
heat during the exercise of this faculty. 
The other properties of the ethiops of platina, as those of 
oxydizing and inflaming spirit of wood, of condensing olefiant 
gas into acetic acid, of transforming sulphurous into sulphuric 
acid, &c. are all founded on this mechanical action of platina 
on oxygen. 
I have never been able to succeed in obtaining an ethiops 
of platina entirely exempt from carbon, for all platina reduced 
by the humid process, even that precipitated by zinc, gives 
out on exposure to a red heat, either pure carbonic acid or 
a mixture of carbonic acid and oxygen. Sixty grains of this 
